Ground engaging unit for ballast tamping machines

ABSTRACT

The ground engaging unit of the invention includes a stem or shaft having an upper tapered portion for connection to a supporting arm of a tamping machine and also having a lower shouldered tapered portion for receiving a replaceable shoe. The shoe has a top opening socket and a lower blade portion. The socket in the shoe is tapered inwardly toward its lower end for receiving the lower tapered portion of the stem. In a first embodiment, the socket receives the stem in a wedging fit. In another embodiment, the stem and socket are held together by a thermoplastic adhesive. Horizontal aligned grooves are provided in the stem and socket of the second embodiment and excess adhesive gathers therein to form connecting rings when hardened.

1111 3,826,025 51 July 30, 1974 GROUND ENGAGING UNIT FOR BALLAST TAMPING MACHINES [76] Inventor: William A. Elliott, 8020 S.W.

Mapleleaf, Portland, Oreg. 97223 22 Filed: Dec.l1, 1972 21 Appl. No.: 313,932

Related US. Application Data [63] Continuation-impart of Ser. No. 23,953, March 30,

1970, abandoned.

[52] US. Cl 37/142 R, 104/12, 173/90,

172/745 [51] Int. Cl E021 9/28 [58] Field of Search 104/10-14;

3,330,055 7/1967 Petersen 37/142 A 3,371,437 3/1968 Wilson et al. 37/142 R 3,520,565 7/1970 Fowler 287/126 3,581,664 6/1971 Kruse 173/90 X Primary ExaminerRobert E. Pulfrey Assistant Examiner-Eugene H. Eickholt Attorney, Agent, or Firm-Eugene M. Eckelman 5 7 ABSTRACT The ground engaging unit of the invention includes a stem or shaft having an upper tapered portion for connection to a supporting arm of a tamping machine and also having a lower shouldered tapered portion for receiving a replaceable shoe. The shoe has a top opening socket and a lower blade portion. The socket in the shoe is tapered inwardly toward its lower end for receiving the lower tapered portion of the stem. In a first embodiment, the socket receives the stem in a wedging fit. In another embodiment, the stem and socket are held together by a thermoplastic adhesive. Horizontal aligned grooves are provided in the stem and socket of the second embodiment and excess adhesive gathers therein to form connecting rings when hardened.

2 Claims, 10 Drawing Figures GROUND ENGAGING UNIT FOR BALLAST TAMPING MACHINES CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of application Ser. No. 23,953, filed Mar. 30, 1970, now adandoned, for DIGGING UNIT FOR BALLAST TAMP- ING MACHINES.

BACKGROUND OF THE INVENTION This invention relates to a new and novel ground engaging unit for ballast tamping machines.

In the leveling of existing railroad tracks as well as in the construction of new tracks, ballast tamping machines have heretofore been used which employ head assemblies capable of digging down, raising the ties and tamping the ground therebeneath. These head assemblies include support arms each carrying a plurality of ground engaging units. These ground engaging units comprise a working blade and an integral stem, the stern being detachably connected to the support arms. When a working blade is worn out, it is necessary to replace the entire unit, including the stem. The beds in which the digging units operate usually comprise packed rock, and such rock or other bed material is very abrasive, resulting in a short useful life of the said blade. The ground engaging units are formed from a tempered steel and are very costly to replace.

SUMMARY OF THE INVENTION The purpose of the present invention is to overcome disadvantages of structure now in use and more particularly has as its primary objective to provide a ground engaging unit for a ballast tamping machine which employs replaceable shoes on supporting stems whereby said shoes can be replaced without also replacing the stems, and also to provide a replaceable blade on said shoes which can be replaced without replacing the shoes.

Another object of the invention is to provide in a first embodiment a novel wedging connection between the stem and shoes, said connection providing a solid but replaceable mounting of the shoes on the stems. More particularly, it is an object to provide in such embodiment a wedging connection between a supporting stem and a replaceable shoe of the type described wherein the shoe has a generally tapered socket for receiving a tapered portion of the stem and also wherein each of the stem and socket has an auxiliary tapered surface extending angularly to the general taper and in the direction of such general taper to supplement the wedging connection.

Another object is to provide a novel connection between a stem and shoe in the form of an adhesive layer, the adhesive layer preferably comprising a thermoplastic substance to facilitate disconnection of the two parts by applying heat thereto. Another object is to provide in such connection horizontal grooves in the stem and shoe for receiving excess adhesive to form connecting rings for holding the shoeon the stem.

Another object is to provide a connection between a socketed shoe portion and a stem wherein the stem has a bottom projecting portion of a smaller diameter than the body of the stem and the outer surface of said body at the upper end of the projection leads upwardly in substantially a flush plane with the outer surface of the shoe portion.

The invention will be better understood and additional objects and advantages will become apparent from the following description taken in connection with the accompanying drawings which illustrate preferred forms of the device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of work head assemblies for ballast tamping machines which include features of the present invention;

FIG. 2 is a side elevational view of a first form of stem forming a part of the present invention;

FIG. 3 is an end elevational view of the stem shown in FIG. 2, taken on the line 33 of FIG. 2;

FIG. 4 is a front elevational view of a shoe portion used with the embodiment of FIG. 2;

FIG. 5 is a sectional view taken on the line 55 of FIG. 4 and showing the shoe installed on the stem;

FIG. 6 is a sectional view taken on the line 66 of FIG. 5;

FIG. 7 is a fragmentary front elevational view of a second embodiment of the invention, the stem not being shown in this view;

FIG. 8 is a sectional view taken on the line 8-8 of FIG. 7 but illustrating the shoe installed on the stem;

FIG. 9 is a rear elevational view of a shoeportion forming a third embodiment of the invention; and

FIG. 10 is a sectional view taken vertically and centrally through. FIG. 9.

Referring in particular to the drawings and first to FIG. 1, the numeral 10 designates conventional railroad ties and the numeral 12 designates the usual rail supported on said ties. When the bed for the ties, designated by the numeral 14, requires leveling, one system for bringing up the sunken portion to grade is by ballast tamping machines. Such tamping machines are of well known construction and employ head assemblies having a plurality of supporting arms 16. The machine itself is not shown in the drawings. The supporting arms are manipulated by suitable power means on the machine and have ground engaging units 17 capable of digging and tamping on opposite sides of a tie in the sunken area to raise the tie while at the same time tamping the bed under it. Such movement of the arms 16 comprises an oscillating movement and generally rotatable in the direction of the arrows 18.

As stated hereinbefore, existing or conventional constructions use ground engaging units 17 of one piece. That is, each said unit comprises a supporting stem adapted for connection to an arm 16 and an integral blade portion. Such has the disadvantage that when the blade portion is worn out the entire unit must be replaced, including the stem.

As will be described in detail hereinafter, the present invention has working blade portions detachably connected to supporting stems. Referring to the first embodiment of FIGS. 2-6, each ground engaging unit 17 comprises a stem or bar 20 having the usual tapered portion 22 adapted to fit in a suitable aperture 23 in a supporting arm 16, the tapered portion 22 having a keyway 24 to provide a key connection in aperture 23. Also, the upper end of the stem 20 is of conventional construction in that it has a threaded extension or stud 26 for engagement by a lock-nut 28 bearing on the upper end of a supporting arm, the upper tapered portion 22 being generally circular in its transverse cross section and thus generally is cone-shaped.

The stem has a lower portion 30 adapted to receive a removable shoe 32. Said lower portion of the stem is tapered in the opposite direction from that of the upper portion 22 and in cross section assumes an elliptical shape, as best shown in FIG. 6. The major diameter of the stem portion 30 is from front to rear since the principal work load or stress on the stem extends in such direction.

The shoe 32 has a body portion provided with a top opening socket 36 which generally is tapered toward its lower end and dimensioned so as to receive the tapered lower portion 30 of the stem in a wedged, friction fit. Thus, the shape of the socket in cross section, similar to the stem portion 30, is elliptical. This shape of the stem and socket prevents any relative rotation of the shoe on the stem.

In order to insure a tight wedge fit between the stem portion 30 and shoe 32 and to position the shoe properly on the stem, the lower tapered portion of the stem is provided with an auxiliary taper 38 on the rearward bottom portion thereof. The socket 36 has a correspondingly tapered surface 40 dimensioned and arranged for engagement by the tapered portion 38 on the stem. The auxiliary taper 40 in the socket is of greater length than the auxiliary taper 38 on the stem so that the bottom end 42 of the stem will never contact the bottom wall 44 of the socket. By means of this construction, the tapered surfaces 38 and 40 insure a frictional, wedge fit in addition to the overall frictional wedge fit between the tapered portions 30 of the stem and the socket 36. The shoe is attached to the stem by hammering it in place and also by applying one or more spot welds 45 between the stem and socket at the top of the latter.

Shoe 32 has a transverse, integral working blade 46 which accomplishes the digging and tamping operations. As is well known in the art, blades 46 may be of any desired shape and length. As an example, such blades may project a greater distance from one side of the shoe for the purpose of working up close to the rails.

When the blade or the shoe becomes worn or damaged, it is merely necessary to remove the shoe and replace it with a new one. It is thus not necessary to replace the entire ground engaging unit as in conventional practice, and a substantial saving results.

The embodiment just described has the important advantage that existing ground engaging units 17 may be rejuvenated by employing principles of applicants invention. That is, when an existiang working blade of the ground engaging unit is badly worn, the lower portion of the stem may also be worn. In such worn condition, the stem assumes a taper substantially that shown in the drawings. To install the shoe forming a part of the invention on an existing work stem, the latter must be cut off adjacent the bottom to remove any remaining shoe portion. Such cut forms the bottom end 42. In addition, said stem is provided with the auxiliary taper 38 for engagement with the taper in the socket. To provide a reasonably good wedge fit between the stem and the socket 36 it may be necessary to grind off certain areas of the lower portion 30 of the stem. The shoe portion 32 may be fitted on existing stems and replaced as often as necessary by first breaking the spot weld in the old shoe, hammering off the said old shoe, andthen installing the new shoe. This may be accomplished without removing the stem from the tamper arm 16. The invention has been described above as employing existing stems 20, but it is to be understood that new assemblies may be manufactured wherein the stems have a suitably tapered lower portion for fitting in the socket 36 and an auxiliary taper 38 for engaging the taper 40.

In the second embodiment shown in FIGS. 7 and 8, a ground engaging unit 17' similarly employs a stem or bar 20 having an upper tapered portion 22 and a top threaded extension or stud 26' for engagement by a lock nut 28 to hold the ground engaging unit on a supporting arm.

The stem 20' has a lower portion 30' with a bottom, smaller diameter tapered portion 31 projecting therefrom adapted to receive a removable shoe 32'. The portion 31 is tapered in the opposite direction from that, of upper portion 22' and is elliptical in cross section as in the FIG. 1 embodiment. The shoe 32 has a top opening socket 36 which generally is tapered inwardly towards its lower end. The parts are dimensioned such that the tapered lower portion 31 of the stem is arranged to be received in the socket 36' in a wedge fit.

The embodiment of FIGS. 7 and 8 not only relies for its connection on a wedging fit but also employs an ad hesive layer between the portion 31 of the stem and the socket 36'. The stem has one or more peripheral grooves 50 and the inner defining wall of the socket 36 has a corresponding number of peripheral grooves 52. As seen in FIG. 8, respective grooves 50 and 52 are in alignment when the stem is inserted in the shoe. According to this construction, a novel connection is provided between the stem and the shoe as follows: Either the outer surface of the lower portion of the stem or the inner surface of the socket or both, is coated with an adhesive and before such adhesive sets up the stem is inserted forcefully into the socket. The layer of adhesive between the two parts is designated by the numeral 54. Excess adhesive 56 will gather in the bottom of the socket and also excess adhesive 58 will flow into grooves 50 and 52 which when set up will form ringlike members to prevent removal of the shoe from the stem as long as the adhesive is set.

The embodiment of FIGS. 7 and 8 provides easy attachment and removal of the shoes 32' from the stem portion 40 in that for installation, the lower portion of the stem and the socket is merely coated with the adhesive and the parts forcefully engaged with each other. Also, sufficient coating of the adhesive is provided to form the connecting rings 58. For this purpose, it may be desirable to pour a small amount of the adhesive in the socket and also coating the lower end of the stem portion 31, such as by dipping it in a supply of the adhe-' sive. When the adhesive is set, a positive connection is provided but at the same time the shoe can be readily removed by heating the parts with a torch for melting the adhesive. To accomplish this purpose, a thermoplastic adhesive is used. Some of the epoxy resins are very satisfactory. The outer surface diameter of the stern portion 30 at the upper portion of projection 31 is about the same as the shoe 32' so that the outer portion of said stem and the top of the shoe form a peripheral abutment and also the shoe and stem are flush with each other at this point. No projecting edges or shoulders thus exist to cause unnecessary wear and the stem has limiting movement into the shoe to align grooves 50 and 52.

FIGS. 9 and 10 show yet another embodiment of the invention which employs a shoe 32" removably attachable to a stem of the type indicated by the reference numeral in FIGS. 7 and 8. Also similar to the embodiment of FIG. 8, the shoe 32" has a top opening socket 36 arranged to receive a lower portion of the stern and attachable thereto by a wedge connection as well as by adhesive placed between the walls of the shoe and the socket and in grooves 52" and corresponding grooves in the stem.

The shoe 32" of FIGS. 9 and 10 is cast with a bottom inset face 60 and has plate-like extensions 62 which project laterally beyond the sides of the body portion of the stem. The forward face of the side extensions 62 extend flush from the face of inset 60 to form a rather wide mounting face for a blade 64. The inset 60 forms a top shoulder 66, and the blade 64 in its position on the shoe lies flush on the face of inset 60 and extension 62 with the upper edge thereon in abutment with shoulder 66.

Connection of the plate 64 to the stem is preferably accomplished by rivets 6 8. These rivets may be four in number and the holes therefor have tapered ends or inset portions 70 for receiving the heads of the rivets so that they will not project beyond the surfaces of the blade 64 or the extensions 62. Such connection has been found to be of substantial improvement over bolts since bolts wear off fast due to the hard usage to which they are subjected. When it is desired to replace the plate 64, the rivets are merely pounded out and a new plate reset by new rivets. Such rivets are preferably constructed of high tensile metal and are installed hot. Such provides an efficient connection which will maintain the plate 64 in place.

According to the embodiment of FIGS. 9 and 10, the plate 64 can be replaced when worn and it is not necessary to replace the whole shoe 32". Such shoe will also eventually wear and when it needs replacement it is removed from the stern and a new one installed. Depending upon the treatment to which the shoe and blade 64 are subjected, the shoe will last for several of the blades 64. Such comprises a substantial saving.

It is to be understood that the forms of my invention herein shown and described are to be taken as preferred examples of the same and that various other changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention.

Having thus described my invention, I claim:

1. A ground engaging unit for a ballast tamping machine of the type having a supporting head assembly driven in a motion to loosen and tamp ground adjacent to and under railroad ties, comprising a. a stem having upper, lower, and intermediate portions,

b. means arranged to removably connect said stem at its upper portion to the head assembly,

c. the lower portion of the stem being tapered smaller toward the bottom,

(I. a shoe member having front and rear portions and also having a lower flat face portion inset in the front of said shoe member to form an upper shoulder,

e. a transverse blade removably attached to the front lower face portion of said shoe member by rivet means in upper abutment against said shoulder,

f. said blade having an upright, flat, plate-like working face at the front thereof for loosening and tamping ground,

g. means in said shoe member defining a top opening socket,

h. said socket being of a shape and size to receive a tapered end portion of said stem in a wedging fit,

i. a bonding layer of thermoplastic resin between said stem and socket of said shoe member,

j. means in the lower portion of said stem defining at least one peripheral groove,

k. means in the defining walls of said socket defining at least one peripheral groove arranged to be aligned with the said groove in said stem whereby both of said groove means are arranged to receive said resin and form a locking ring between said stem and shoe,

1. the upright dimension of said socket being greater than the length of said lower portion of the stem to receive excess resin below the stem,

m. the cross sectional dimension of said intermediate portion of the stem at the lower end thereof being greater than the top of said socket to form an abutment for engaging the top of said shoe member to limit the inserted distance of said lower portion of the stem into the socket and align the peripheral grooves in said stem and the defining wall of said socket.

2. The ground engaging unit of claim 1 wherein said stem has an auxiliary taper on one side leading upwardly from the bottom thereof, said auxiliary taper extending angularly to the general taper of the stem and in the direction of such general taper, said socket also having an auxiliary taper, said auxiliary taper in the socket leading upwardly from the bottom thereof and extending angularly to the general taper of the socket and in the direction of such general taper, said two auxiliary surfaces being engageable to position the stem selectively in said socket. 

1. A ground engaging unit for a ballast tamping machine of the type having a supporting head assembly driven in a motion to loosen and tamp ground adjacent to and under railroad ties, comprising a. a stem having upper, lower, and intermediate portions, b. means arranged to removably connect said stem at its upper portion to the head assembly, c. the lower portion of the stem being tapered smaller toward the bottom, d. a shoe member having front and rear portions and also having a lower flat face portion inset in the front of said shoe member to form an upper shoulder, e. a transverse blade removably attached to the front lower face portion of said shoe member by rivet means in upper abutment against said shoulder, f. said blade having an upright, flat, plate-like working face at the front thereof for loosening and tamping ground, g. means in said shoe member defining a top opening socket, h. said socket being of a shape and size to receive a tapered end portion of said stem in a wedging fit, i. a bonding layer of thermoplastic resin between said stem and socket of said shoe member, j. means in the lower portion of said stem defining at least one peripheral groove, k. means in the defining walls of said socket defining at least one peripheral groove arranged to be aligned with the said groove in said stem whereby both of said groove means are arranged to receive said resin and form a locking ring between said stem and shoe,
 1. the upright dimension of said socket being greater than the length of said lower portion of the stem to receive excess resin below the stem, m. the cross sectional dimension of said intermediate portion of the stem at the lower end thereof being greater than the top of said socket to form an abutment for engaging the top of said shoe member to limit the inserted distance of said lower portion of the stem into the socket and align the peripheral grooves in said stem and the defining wall of said socket.
 2. The ground engaging unit of claim 1 wherein said stem has an auxiliary taper on one side leading upwardly from the bottom thereof, said auxiliary taper extending angularly to the general taper of the stem and in the direction of such general taper, said socket also having an auxiliary taper, said auxiliary taper in the socket leading upwardly from the bottom thereof and extending angularly to the general taper of the socket and in the direction of Such general taper, said two auxiliary surfaces being engageable to position the stem selectively in said socket. 